Method of reconditioning boilers



June 6, 1944. F. w. MILLER METHOD oF REcoNDITIoNI'NG BILERs Filed Nov. 29, 1941 f INVENTOR. Hm@ MMM@ Patented June 6, 1944 METHOD OF RECONDITIONING BOILRS Frank W. Miller, chicago, 111.', assign@ to' Franclare Company, Chicago,`1ll.,r ak'corporation of Illinois Application November 29, 1941, Serial Yblo. #420,915

1, Claim.

This invention relates to the reconditioning of steam boilers by reducing the concentrates in the boiler Water while the boiler is under steam pressure, thereby eiecting a great saving in the idle time of a boiler over the practice of completely blowing down the boiler and then reiilling it. Furthermore, by maintaining the boiler under steaming pressure and temperature during the reconditioning, the injurious effects occasioned by cooling down and reheating the boiler resulting in the unequal stresses and strains imposed thereon are obviated.

The present invention constitutes an impro-vement upon the method disclosed in my prior application Serial No. 300,329, iiled October 20, 1939, in that its use in essential respects is not dependent upon an available supply of extraneous steam. While stationary as well ias portable boilers may be reconditioned with my present invention, it is particularly valuable for' the reconditioning of locomotive boilers. The fact that an available supply of extraneous steam is not essential, renders the use of my invention in connection with locomotive boilers possible at roundhouses and stations not equipped with power boilers and under conditions which have heretofore been deemed unsuitable for the accomplishment of the purposes for which my present invention is designed.

Furthermore, the apparatus by which my method may be practiced involves novelty in designand operation which makes possible the reconditioning of boilers in a most efcient and economical manner.

The present practice on some railroads is to clarify or purify the boiler water of the locomotives by reducing the concentrates therein without completely blowing down, washing out and relling the boiler except at periodic intervals of considerable length. According to this method approximately 600 gallons of the contaminated water will be blown olf, whereupon, by means of the locomotive injector, the blown off water will be replaced with water from the tender at a temperature of from 40 to 50 F. Such blowing oi vand replacing operations will be repeated two or three times morder to produce a satisfactory water condition in the boiler, since each '600 galvlon blow-off will customarily reduce the boiler concentrates approximately ten grains.- Ilfhe temperature ofthe water introduced by the injector is raised by the injector steam to the neighborhood of 160 F., but this is relatively so lcold in comparison with the water in the boiler,

which at 150 pounds of steam has a temperature F of 365,: that the'introduced water sinks rapidly to the bottom of the shell, thereby cooling the shell and imposing excessive strains of contraction and expansion thereon, and also cools the walls of the nrebox, thus impairing the combustion of the fuel. r i

During the successive water blow-os and replacements in accordance with this method, the locomotive is continuously red and maintained under a forced draft Ato heat as rapidly as possible the cold water introduced into the boiler. It has been demonstrated that for each 600 gallons of water change effected in accordance with this method, a coal consumption oi approximately 600 pounds is required to heat the water thus introduced. Four blow-offs of 600 gallons each which aggregate approximately one-third the capacity of a modern boiler, requires a coal consumption of approximately 2,400 pounds to restore the Water temperature and steam pressure to normal operative condition in the boiler.

In accordance with my present invention, the same reduction of boiler concentrates is effected in a much shorter period of time, the boiler tem- ;-o perature is not reduced sufficiently to produce injurious strains Iand stresses in the boiler shell, and the fuel required to restore the boiler tonormal working Water temperature and steam pressure is only approximately fifty per cent. of that at present required in the practice of the method above outline.

Briefly stated, my improved method by which the above mentioned advantageous results are attained involves the same partial blowing down and wate;` replacement operations as are employed in the injector method above described. The blown off W'atenfhowever, instead of being thrown away, is conserved to the extent that its heat units are transferred to the clean refill waterV so as to raise the temperature of this water to somewhere in the neighborhood of 180. The apparatus for thus transferring the heat units is not herein shown on the drawing, as it is of well known character such, for instance, as that shown in my prior Patent No. 2,260,857, issued October 28, 1941. This partially heated refill water is then deliveredunder pressure to la heater or heat booster such as shown in Fig. 3 of said patent, where the rell water is heated to a temperature of approximately 300 F., by admixing therewith 'water at high temperature taken from the boiler being conditioned. Assuming that the steam pressure in such boiler is ata normal of 150 pounds; the waterdelivered-from the boiler to the heater for admixture with-the refill water will be at a temperature of approximately 365 F. The ultimate mixture of refill and boiler waters will have an intermediate temperature, depending of course upon the relative proportions of such waters delivered to the heater, but under normal conditions its temperature will approach 300, which is obviously so much hotter than the 160 water delivered to the boiler by the injector method that rino injurious cooling Lrif 'lthe boiler shell will result and the water temperature and steam pressure in the boiler will not be unduly lowered. This hot mixture is delivered under pressure to a pump which raises 'it'sipressure-s'ufflciently above the pressure existent in the boiler to cause its delivery into the boiler against the boiler pressure. In this manner thev boilr is maintained at high temperature and under steam pressure during the reconditioningfso'fthatthe unfavorable conditions created by the `injector method of reconditioning are obviated, the reconditioning i's laccomplished Iin a shorter time Ia'n'd tlfe Fboil'r is ilresto'r'ed to inoimal working tem--l pi-atii-ie fand. pressu're `"with @La ffu'el lc'onsumption of Iapprxirnately one-half fthat required by the injecter method For the purpose of facilitating an understanding diirnyiinventionbne termici-'novel apparatus by w-ienrny method maybe/carried out .isishown onithelaceonipanyingidraw yfg,--re'ferrin'g'tcvlwhiclm aug. 2 is :a iherizentalfseetional x/iiewon :the line 2f-e-'2e`f` `g.-1. i. f The wing efxemplis er1-installation oflm'y nof` appamtusalbng side Ea Ytra'ck'lupon which the Ll'o'ciifiotivefto beireoondition'e'distands. zUsu'ally, altho't'glfi#not in'ecessarily, :the installation wwill be linade 1in a rbndhouse 4-and the apparatus Lloca'ted fbetwen two :adjacent xlocornotivelstalls, so that :1t lmy libe connected to rand employed-'tor conditioning `'a boiler of 'alocomotive :standing in eitnepstau, Y L v 1A -Tbur'idiiouseiada'pted foriboiler .washing .and re'illin iis usually equipped, :illustrated in -1,withialblow-oifilineE :through whichthe-blown eff products are delivered :to :suitable -heat :conservingiequipment, fsuch, f'or. instance, :as that ill-ustratedfin f my sprior patentrabovereferred to. A Fcustomary installationf.also includes .the rell lil-hei @by whichurell water fwhichfhasb'eenpartially heated by the blown off products :is -conveyed to the -flocomotivesffor refilling purposes. lhose Lroimrlheuses which .have repair 4shops Vinciudingip'ower operatedsmachines:associatedzwith themare usuallyp1evidedalsofwith a 'steam sup- .ply-'line flwhichueceivesits-"steam from thepower boilers. Suchfa steamfsupplysfn'ot essenitalzto thespracticingof"myrimprevedimethod:.or the operation "of my. nov'e'lL-apparatus,V '-but -in installations whereisuch/steamgisfavailable it may be connected to #my rfappara'tusias sa means of heatzingrreill water-:roi lfcompletely:refilling'fa locomotive which.' hast-been completelyblown 'down and washed-lout. c Y

lllinefiscnnecte yaiiro'pi with Aa iheaterriheat booster 9h he. type-'disclosedLi-n my isaidiprior. patent, :'Whichicomprises 'Venturi tube sII finto whichftiiefrefillwater, from thepipe 43 i's 'Ldeliveredi'byaa:nozzle I12. The supply of vre- -nil iw'ater Sso ideliv'ered should kvbe :subject to kcontrol A"and, regulation; land, in order xto -obviate the necessity of `raccurate a'di,ustnfientforffsettingsA f aa "singlevcc-ntrol -valvefl fpreter'to:interposeabetween -the .pipe 8 and the @heater it 9 a plurality pf,

shunt pipes aggregating in cross-sectional area the area of pipe 8. Each of these branch pipes is equipped with a control valve I4 which will a1- Ways be either fully open or fully closed. In this manner the quantity of refill water delivered to the heater is regulated by the number of valves opened, thereby obviating the danger of imperfect control resulting from the careless setting of a 'single control'valve. The pressure fof the rell water entering the heater may beascertained from a pressure gauge I5.

'A pipe I6 communicating with the chamber of the 'heater rsurrounding the nozzle I2, is provided at its outer end with a flexible conduit, herein illustrated ascomprising a plurality of pipe s'e'c'tions 'I1 and ball connections I8 affording the requisite exibili'ty A threaded connecting element vI9 l'aiords .provision for connection to a boiler shell, such connection being usually made through the blow-01T cock opening into the boiler located-'at'aflow level in the -b'oilerfleg `2 I, :as-illustrated. A Aconventional boiler -22., shown in=dot ted flines, includes a ltypicall steam-dome `.23. :Pipe llvisprovided with-ashut-of valve-24 yand 'a similar valve C25 is preferably located in vthe :flexible connection near the point -of attachment `to 'the boiler.

lFrom the heater -9 ya pipe 26 leads Ito thefintake of ra :pressure pump -21 Tdriven by a motor 28. For .convenience, pipe 26 iis provided with-a 4thermometer--29. -The pump is r:adapted ato raise the pressure of the fluid handled about 2,5 pounds, and :the iiuid is delivered through pipe -2YI -and suitable exible Iconnections to the boiler, Ypreferably fthrough'the dome 23.

The .first ystep in reconditioning a boiler in accordancegwith my method is Vto blow-.off approximatelySOOsgallons of contaminated water. This water is -deli-veredfinto .the |boiler washing and relling system where its :heat is utilizedito heat .fresh --reilling water in a well-known manner. In orderj-to'blowpff `this water, kthe connection I9 `isattached 4to .the .boiler shell. Valve 24 is closed, valve 3.2 in vbranch pipe .33 :is opened, Yval-ve 34 at-the suction side of the -pump .is closed,and valve`35ina-pipe-i36 Aleading vfrom .a heater 9 to the blow-offfline --s-opened Upon -opening -valve :25, the contaminated .boiler -water is blownthrough connections. 'I,pipe.33,.pipe-26,

.the lower portion-of heater `9,;pipe 36,and blowoff line 5 Ato .the Vheat -coriserving apparatuscfthe boiler :washingnand .reiillingrisystem. When -the 'boiler-gauge glass shows that-the desired amount of contaminated water has been blown-olf, valves 35 vand 32 are closed, valve-3'4isopened, androne or more .of valves I4 is opened. This .permits Va delivery of clean refill water f'frdm the .rell lline r6 Ito the heater, where Vit fis Adischarged by `the nozale 'I2vin'to vthe venturi I'I and thence `to :the `intakefside ofthe pump. This drefill water .will be at `a temperature ranging `between 1`60 and 1 80" E, and u ncler an `approximate :pressure -of 200 .pounds The YValve 2d-is then .opened permitting ,the -deliveryof water from fthe boiler .to (the upperA chamber. of the heater 9, from whence -it is `v.draw-n through the venturi 'II by -fthe ,jet .issuing vfrom norzvzrle I 2, so that -this -water is thoroughly .mixed with the refill -water to pro- -duce aresultant mixture of high temperature. `While the `-proportions of :,rell water :and vblowoif water may .be vvaried-by manipula-tion of valves I4 and 2.4,fsatisfactoryfresultsfunderlnor- .mal conditions-,are obtained i by Ta` deliveryit'o :the heater of refilling Y water f and blow-off wwa'ter fin :the :present finstance 7three,smallerbranch =or -.75 slibsiantallyethe .fproportionsoff one t'to -two,\that is, if valves I4 permit a flow of refill water at a rate of approximately 40 gallons per minute, the blow-off water delivered to the heater from the locomotive will be approximately 80 gallons per minute. If the pressure of the boiler is in the neighborhood of 150 pounds, the Water blown off will have a temperature of approximately 365 F. The resultant mixture of one gallon of rell water at a temperature of 180 with two gallons of blow-off water ata temperature of 365 will have a temperature of approximately 300 F., and be delivered to the suction side of the pump, under a pressure somewhat below the boiler pressure but suiflcient to prevent steam flashing of the superheated mixture.

The pump is adapted to raise the pressure of the heated mixture of fresh and boiler Waters to a point above boiler pressure, so that it will be delivered through the line 3| into the boiler at any preferred point, such, for instance, as through the steam dome as illustrated on the drawing. When the water level in the boiler has been restored to normal by the introduction in the manner described of approximately 600 gallons of refill water, the valves I4, 24, and 34 are closed and valves 32 and 35 are opened to permit another blow-oil from the boiler. When the desired amount has been blown off, this amount is again replaced with refilling water in the man ner described and such alternate blowing off and replacing operations may be continued until the desired reduction in concentrates of the boiler water has been attained. In practice, three or four partial blow-downs are sufficient to produce a satisfactory water condition in the boiler.

While I have described the blow-down and water replacement operations as being performed in alternation by the apparatus described, it should be understood that if the roundhouse is equipped with my apparatus on each side of the locomotive, the blow-down may be performed on one side of the locomotive by one apparatus while the water replacement or refill is simultaneously performed by another apparatus on the other side of the locomotive. Such practice obviously results in a considerable saving of time over the alternate blowing down and relling, and the ultimate results within the boiler are the same in both instances.

In addition to its function of reconditioning boilers by a succession of partial blow-downs and reiills, my apparatus is also adapted for completely blowing oi and refilling boilers with hot water where the roundhouse is equipped with the live steam pipe 1 and suflicient steam for heating purposes is made available by the power boilers. In such instances a pipe 31 connects the steam line 1 yvith the pipe I6 leading to the heater, and a shut-off valve 38 is interposed in pipe 31'. If a boiler is to be completely blown down,

the partial blow-down procedure is continued until complete blow-off has been accomplished. In such instances, the boiler is usually washed out and perhaps subjected to repair work, and upon relling the partially heated refill water, instead of being further heated by blow-off water from the boiler, is heated by steam from the line 1. To accomplish this result, valve 24 is closed and valve 33 is opened, whereupon the refill operation will proceed in the manner described in detail in my prior Patent No. 2,260,857.

To obviate possible air locking or steam locking of the pump 21 resulting from careless or improper manipulation of the apparatus, I have provided a relief pipe 39 extending from the pump casing to the pipe 36, and pipe 39 is equipped withk a shut-off valve 4| which, in the event of such locking of the pump, may be opened to relieve the lock.

Vertical supporting posts are customarily located between the pits or stalls in a roundhouse. One of such posts indicated by reference character 42 is shown in Fig. 2, from which it will be apparent that the design of my apparatus is such that the post does not interfere with its installation or operation. To avoid confusion, the post is not shown in Fig. 1.

From the foregoing it will be manifest that by my improved method and apparatus a boiler may be reconditioned by reducing the boiler water concentrates without subjecting the boiler shell to injurious stresses and strains such as are incident to the introduction of cold or cool water into the boiler. The boiler water itself is used as the heating medium to raise the temperature of the reiilling water to a point where no injury to the boiler shell will result from its introduction, and the pressurerequisite for the introduction of the refill water against vthe boiler pressure is provided by a pump capable of increasing the pressure the requisite amount over that existing at its intake.

The structural details illustrated and described may obviously be varied within wide limits without exceeding the scope of my invention as defined in the following claim.

I claim:

The method of reconditioning steam boilers while under steam pressure, which consists in blowing off a portion of the contaminated boiler water,introducing into a heater refill water adapted to replace said drawn off water, introducing into said heater water from the boiler whereby to heat the refill water to a temperature suitable for introduction into the boiler, then raising the pressure of said heated water to a point above the pressure existent in the boiler and delivering saidv heated water into the boiler.

' FRANK w. MILLER. 

